cannot determine the relationship

Hi,

I have two tables, both with a code field that I want to join, but both are many.

I have therefore created a table with a code column that has unique codes only, and I ahve used this to try and join them.

i.e. the many to many has instead become a one-many and a one to many.

However I am getting the error that Power BI cannot determine the relationship between fields.

Help??